From 4a7da93bdbfcd166f5bb67a69d6f017da158c7e2 Mon Sep 17 00:00:00 2001
From: David Brazdil <dbrazdil@google.com>
Date: Fri, 9 Jul 2021 11:47:09 +0100
Subject: [PATCH] ANDROID: KVM: arm64: Read and check S2MPU_VERSION

Read S2MPU_VERSION during driver init and check it against list of
supported versions. The register fields are as follows:
  - MAJOR_ARCH_VER,
  - MINOR_ARCH_VER,
  - REV_ARCH_VER,
  - RTL_VER.
Their exact use is not documented. For now, we mask out RTL_VER and
expect a match on MAJOR_, MINOR_ and REV_ARCH_VER. This may be tweaked
in the future.

Test: builds, boots
Bug: 190463801
Signed-off-by: David Brazdil <dbrazdil@google.com>
Change-Id: I2fbd20ab78a992c8bdb3574a6d480012260c9ded
---
 arch/arm64/include/asm/kvm_s2mpu.h | 17 +++++++++++++++++
 arch/arm64/kvm/iommu/s2mpu.c       | 12 +++++++++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_s2mpu.h b/arch/arm64/include/asm/kvm_s2mpu.h
index ba0db7988117..2ae35aba43e6 100644
--- a/arch/arm64/include/asm/kvm_s2mpu.h
+++ b/arch/arm64/include/asm/kvm_s2mpu.h
@@ -7,6 +7,23 @@
 #ifndef __ARM64_KVM_S2MPU_H__
 #define __ARM64_KVM_S2MPU_H__
 
+#define REG_NS_VERSION				0x60
+
+#define VERSION_MAJOR_ARCH_VER_MASK		GENMASK(31, 28)
+#define VERSION_MINOR_ARCH_VER_MASK		GENMASK(27, 24)
+#define VERSION_REV_ARCH_VER_MASK		GENMASK(23, 16)
+#define VERSION_RTL_VER_MASK			GENMASK(7, 0)
+
+/* Ignore RTL version in driver version check. */
+#define VERSION_CHECK_MASK			(VERSION_MAJOR_ARCH_VER_MASK | \
+						 VERSION_MINOR_ARCH_VER_MASK | \
+						 VERSION_REV_ARCH_VER_MASK)
+
+enum s2mpu_version {
+	S2MPU_VERSION_8 = 0x11000000,
+	S2MPU_VERSION_9 = 0x20000000,
+};
+
 enum s2mpu_power_state {
 	S2MPU_POWER_ALWAYS_ON,
 	S2MPU_POWER_ON,
diff --git a/arch/arm64/kvm/iommu/s2mpu.c b/arch/arm64/kvm/iommu/s2mpu.c
index 9a9e2db44037..5d7a87dee0d3 100644
--- a/arch/arm64/kvm/iommu/s2mpu.c
+++ b/arch/arm64/kvm/iommu/s2mpu.c
@@ -18,7 +18,7 @@ static int s2mpu_probe(struct platform_device *pdev)
 	void __iomem *kaddr;
 	size_t res_size;
 	enum s2mpu_power_state power_state = S2MPU_POWER_ALWAYS_ON;
-	u32 power_domain_id = 0;
+	u32 version, power_domain_id = 0;
 	int ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -58,6 +58,16 @@ static int s2mpu_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	version = readl_relaxed(kaddr + REG_NS_VERSION);
+	switch (version & VERSION_CHECK_MASK) {
+	case S2MPU_VERSION_8:
+	case S2MPU_VERSION_9:
+		break;
+	default:
+		dev_err(&pdev->dev, "unexpected version 0x%08x", version);
+		return -EINVAL;
+	}
+
 	return 0;
 }